Microsequencing of the signal peptides from pre-alpha subunits synthesized in cell-free systems reveals the strict conservation of at least 8 hydrophobic amino acids among 3 different species and 4 different tissues. Tunicamycin causes the formation of nonglycosylated alpha subunits which can be secreted but cannot combine with beta subunits. Free and combined alpha subunits appear to have a different carbohydrate structure. Deglycosylation of HCG-alpha with a mixture of exoglycosidoses prevents its recombination with intact glycosylated HCG-beta.